Joint hybrid-precoding design for MU-MISO systems with a subconnected architecture

Abstract In this study, we propose a joint hybrid-precoding algorithm for multiuser multiple-input single-output downlink systems. Specifically, consider that the base station employs an energy-efficient subconnected (SC) architecture with fixed equal subarrays (FESA) (SC-FESA). Optimizing analog precoding matrix in SC-FESA is challenging due to its unique constraint structure. maximize system sum rate, efficient method transform system’s sum-rate optimization problem into continuous and differentiable objective function wherein only nonzero elements of are optimized. For formulated problem, develop alternating (AO) approach jointly optimize digital precoders succession by maximizing rate. proposed AO method, when precoder fixed, employ Riemannian conjugate gradient generate precoder. Furthermore, use minimum mean squared error obtain Numerical simulation results show improves rate energy efficiency compared existing algorithms.